1. Field of the Invention
The present invention relates to a hyper-branched polymer, and in particular relates to the formula thereof and a method for manufacturing the same.
2. Description of the Related Art
Dendritic polymers are belonging to a special class of macromolecules. Generally, dendritic polymer is a polymer with a hyper-branched or arborized structure, and its solubility is higher than a linear polymer with a similar structure due to its hyper-branched structure having characteristics such as loose molecular packing, larger free volume, and less molecular chain tangling. According to branch degree, the polymer can be categorized to two types as below.
(1) Dendrimer, synthesized by divergent or convergent approaches. In the divergent approach, the structural size is divergent from the core to outer-layer by several generations. In the convergent approach, the branch is firstly synthesized and then symmetrically grafted to a core. The dendrimer structure us symmetrical and almost spherical, and the theoretical degree of the branch thereof is 1. Because of its special structure, the dendrimer has individual physical and chemical properties such as excellent solubility, low viscosity, amorphism, and a great amount of terminal groups. However, the synthesis of dendrimer is repeated by adding protective groups, deprotection, and purification, such that synthesis is difficult and yields are low. Therefore, the cost of dendrimer is expensive and not feasible for mass production.
(2) Hyper-branched polymer: synthesized from ABx monomer (x is an integral greater than or equal to 2) by one step polymerization, such that the hyper-branched polymer structure is irregular compared to dendrimer. The degree of the branch of the hyper-branched polymer is about 0.5. Formula 1 shows the synthesis of hyper-branched polymer from AB2 monomer, wherein A and B are reactive functional groups, and ab is the condensation segment of A and B. The resulting hyper-branched polymer structure has a great amount of terminal groups to further modify materials for improving material physical properties. In addition, the hyper-branched polymer also owns some individual properties of the dendrimer, however, it is simpler in synthesis and better in molecular structural control. Hyper-branched polymers have unique properties such as completely amorphous, highly soluble in common organic solvent and processible because of the highly branched nature. The hyper-branched polymer has excellent solubility and a simpler manufacturing process, thereby attracting industry and academia attention for increased research and development.

In Functional Material (Japan), vol. 26, No. 8, page 44-52 (2006), Emeritus Prof. Tsueyuki Sato of Tokushima University disclosed “Nanosize hyper-branched polymer”. This paper alludes that the hyper-branched polymer is generally synthesized from AB2 monomer by one-pot reaction, and tagged as an initiator-fragment incorporation radical polymerization (IFIRP). The combination of the monomer and initiator in the IFIRP, called inimer, is limited in types and application manners. The synthesis utilized inimer has low yields and low controbility of molecular structure and molecular weight, such that its applications are restricted. The chain transfer agent and recombination inhibitor can be applied in the initiating step for improving the yield and controbility of the hyper-branched polymer synthesis, however, it will increase steps and complexity of the synthesis.